Method and device for bending wire-and band-shaped material to closed preferably annular shapes,particularly for automatic benders

ABSTRACT

A METHOD AND DEVICE FOR BENDING A WIRE- OR A BANDSHAPED MATERIAL INTO A CLOSED SHAPE PREFERABLY AN ANGULAR ONE. IN THE METHOD THE ENDS OF THE MATERIAL TO BE BENT ARE BENT FIRST IN A QUARTER CIRCLE AND THEN IN THE SECOND STEP OF THE OPERATION THE CENTRAL SELECTION OF THE MATERIAL IS BENT IN A HALF CIRCLE. IN THE APPARATUS THE TOOLS ALL MOVE IN THE SAME DIRECTION WITH CENTRAL PORTION OF THE TOOL BEING SEPARATETLY MOVABLE TO HOLD THE MATERIAL TO BE BENT AGAINST A COUNTER BLOCK. AFTER THE OUTSIDE PORTIONS OF THE TOOL BEND THE QUARTER CIRCLES ON THE EXTREMITIES OF THE MATERIAL BY SHAPING IT OVER THE BLOCK, THAT PART OF THE BLOCK IS WITHDRAWN TO LEAVE A ROUND CENTRAL PORTION OVER WHICH THE REMAINING HALF CIRCLE IS BENT BY MOVEMENT OF THE CENTRAL PORTION OF THE TOOL.

Feb. 23, 1971 4 HNZER 3,564,899

METHOD AND DEVICE FOR BENDING WIRE AND BAND-SHAPED MATERIAL TO CLOSE-D PREFERABLY ANNUIJAR SHAPES, PARTICULARLY FOR AUTOMATIC BENDERS Filed Feb. 5, 1968 5 Sheets-Sheet 1 Fig 1 PRIOR ART i /2 Inventor:

H-El/VZ. F/A/ZEK Arm/QM 13/3 Feb. 23, 1971 H FlNZER 3,564,899

METHOD AND DEVICE FOR BENDING WIRB- AND BAND-SHAPED MATERIAL TO CLOSED PREFERABLY ANNULAR SHAPES, PARTICULARLY FOR AUTOMATIC BENDERS 5 Sheets-Sheet 2 Filed Feb. 5, 1968 Inventor:

Feb. 23, 1971 FWZER 3,564,899

METHOD AND DEvIcE FOR BENDING WIRE- AND EAND-SEAPED MATERIAL To CLOSED PREEERABLY ANNULAR SHAPES, PARTICULARLY FOR AUTOMATIC BENDERS Filed Feb. 5, 1968 Inventor: A

f EM/A Feb. 23, 1971 FlNZER 3,564,899

METHOD AND DEVICE FOR BBNDING WIRE- AND BAND-SHAPED MATERIAL TO CLOSED PREFERABLY ANNULAR SHAPES, PARTICULARLY FOR AUTOMATIC BENDERS 5 Sheets-Sheet 4 Filed Feb. 5, was

Inventor:

v ,HE/ML Fm LEA 0- I I A Feb. 23, 1971 H, ER 3,564,899

METHOD AND DEVICE FOR BENDING WIRE- AND BAND-SHAPED MATERIAL TO CLOSED PREFERABLY ANNULAR SHAPES, PARTICULARLY FOR AUTOMATIC BENDERS Filed Feb. 5, 1968 5 Sheets-Sheet 5 Inventor.- REWZ FHJZEK HTTDRMbyQ United States Patent US. Cl. 72-404 2 Claims ABSTRACT OF THE DISCLOSURE A method and device for bending a wireor a bandshaped material into a closed shape preferably an angular one. In the method the ends of the material to be bent are bent first in a quarter circle and then in the second step of the operation the central selection of the material is bent in a half circle. In the apparatus the tools all move in the same direction with central portion of the tool being sepaartely movable to hold the material to be bent against a counter block. After the outside portions of the tool bend the quarter circles on the extremities of the material by shaping it over the block, that part of the block is withdrawn to leave a round central portion over which the remaining half circle is bent by movement of the central portion of the tool.

The bending of wireor band-shaped material to rings or other products is carried out generally in two or more operations: first the center part of the length of material to be worked is bent 180, i.e. in U-shape and thereafter the straight legs of the U are each further deformed by a 90 bend. In the devices known up to now these operations were carried out by several tools working in different direction as shall be shown in detail later on the basis of drawings. These tools working in different directions confront the designer with problems in the field of drive and control often and lead easily to a deviation and bending of the pre-bent workpieces in the following operations and thus to a high scrap rate. The method according to the invention eliminates these disadvantages and additionally requires only tool movements in one single direction, so that also the drive and the adjustment of the corresponding devices are very much simplified. The essential feature of the device according to the invention consists in prebending in a first operation the extremities of the workpiece to be worked of wireor band-shaped material by 90 each, while in a second operation the center of the material length is bent further by the remaining 180 in such a way that the pre-bent extremities form a closed structure.

If the method according to the invention is used for bending wireor band-shaped material to rings or the like, there will be, in addition, other advantages to be explained later, above all very simple tool arrangements which must carry out only movements in one direction.

The new method and the devices for carrying it out are best understood in a diagrammatic representation of known arrangements and known methods in comparison with the advantages of the new method as explained in view of a description of the fnuction.

FIGS. 1 and 2 show diagrammatically two known tool arrangements in which, according to known procedure, the material length to be worked is bent in a first opera tion in its center to form a U, while in a second operation the extremities are further bent by 90 each.

FIGS. 3 and 4 are embodiments of a device for carry- 3,564,899 Patented Feb. 23, 1971 ice ing out the new method. FIG. 3 showing an elevational view.

FIG. 4 is a sectional view along line 44 of FIG. 3.

FIGS. 5 and 6 show alternative embodiments useful for additional calibration.

In all the figures the severing device cutting the material to work length is not shown.

The prior art tool arrangement as shown in FIG. 1 has a round center pin 1 and three bendin tools 2, 3 and 4 working in a radial direction. In the middle axis of the bending tool 2 a further tool 5 is arranged which serves to hold fast the length of material 6 during the second operation. The inlet direction of the material is shown as a dash-and-dot line.

In the first operation the length of material 6 is bent by 180 into the shape of an inverted U around the pin 1 by lowering the tools 2 and 5 which are at the same level. Thereafter the tool 2 is moved up again while the tool 5 remains down to hold fast the length of material. In the second operation the tools 3 and 4 are moved radially towards the pin 1 and bend the extremities of the pre-bent length of material 6 to a circle.

In FIG. 2 a known device working in a similar manner is shown in which the first operation is carried out in the same manner as described before.

The center of the length of material 6 is bent in the same manner by the two tools 2 and 5 so as to form an inverted U, the pre-bent length of material is held fast by the tool 5 remaining lowered and thereafter the tools 7 and 8 slide, in this case parallel to the inlet direction of the wire towards the pin 1 to bend the straight legs of the U to form a ring. These two known devices have the big disadvantage that the tools of the second operation work in a direction different from those of the first and therefore make necessary rather complicated drive elements.

They both use the same known bending method, viz to pre-bend first (in the first operation) the center of the length of material to be worked by 180 and thereafter to bend in the second operation the straight extremities by each to form a ring.

The device for carrying out the method according to the invention shown in the FIGS. 3 and 4, works according to another method, which makes it possible for the tools of both operations to work in one direction. According to the invention the extremities of the length of material to be worked are bent in a first operation by 90 each (about in the shape of a letter C lying sideways) in a second operation the center of the length of material is bent by Thereby the pre-bent extremities are joined to form a full circle.

The device for carrying out the method according to the invention (FIG. 3) again contains two tools 8 and 10 moving within each other in a vertical direction from top to bottom. The tool 10 slides inside a tool 9 working in the same direction which has at both sides of the tool 9 work surfaces in the shape of a quarter of a circle. As a counter tool a rectangular block 12 is used, the upper edges of which have likewise the form of quarters of circles. In the middle of the block 12 a round pin 15 is provided. The block 12 is movable perpendicular to the plane of the drawing.

At the beginning of the first operation the tool 8, 11 moves in direction Y simultaneously with the tool 9, the flat work surfaces of which lie at the same level as the flat work surface of the tool 8, 11, towards the block 12 and first bends (contrary to the devices described before) first the extremities of the material length 6 by 90 each. In this movement the lateral straight work surfaces of tool 9 press the length of material 6 against the straight upper edge of the block 12 so that the material cannot deviate upward.

The second operation begins by pressing the length of material, bent at its extremities and having now approximately the shape of a sidewise C, against the pin 15 by means of the tool 10, while the block 12 is moved away orthogonally to the plane of the drawing. This movement may be obtained e.g. directly by wedge surfaces at the tool 10. Thereafter the tool 9 moves downward and bends, with its arcuate Working surface, the center of the length of material 6 for the remaining 180.

As the device for carrying out the method according to the invention offers during the operations an essentially longer guide for the length of material to be bent than the devices known up to now, it is thus even possible for the first time to bend band-shaped material on edge.

For this purpose only a slight modification of the device according to FIG. 3 is necessary as is shown in FIG. 4. All the Work surfaces of the tools 9, 10 and 11 are given narrow grooves 13 (FIG. 4) which are chamfered towards the outside. In FIG. 3 the course of these grooves 13 is shown merely by interrupted lines, while FIG. 4 shows the section through a tool with groove.

By long guiding of the material to be worked in the tool, as compared with the known devices, and by the fact that all the tool components work in the same direction, a deviation of band-shaped materials, even if bent on edge, can be avoided. With the new device it is even possible to bend washers and the like from band material which up to now had to be stamped from sheetrnetal with great loss of material.

It is self-evident that tools and the corresponding counter-tools may also be shaped in such a way that not only purely circular, but also other preferably closed structures, such as oval or other shapes are bent. The essential point of the method to bend in the first operation first the extremities of the length of material in such a way that they join each other when the center is bent in the second operation to form the desired structure.

What is claimed is:

1. A method of bending wire or strip material into a closed product comprising:

(a) placing a workpiece on a convex shaped mandrel;

(b) bending each of the ends of the workpiece a quarter turn by moving a tool having a central morlleable section against the workpiece and mandre moving the mandrel in a direction perpendicular 4 to the movement of the tool to place said workpiece on a second section having an external shape corresponding to that of the interior of the desired finished product;

(d) forming a U-shaped bend centrally between said quarter turns by moving the tool having a central moveable section in the same direction against said workpiece and said second mandrel section thus closing said workpieces into the desired closed product around said second mandrel section.

2. A device for bending wire or strip material to rings or similar preferably closed products comprising:

(a) a moveable tool;

(b) a mandrel having a first portion with work sur faces to form quarter circles at the ends of the material to be worked and a second portion having a shape complementary to the desired shape of the closed product;

(0) means to move said tool towards and way from said mandrel;

(d) means to move said mandrel in a direction substantially perpendicular to the direction of movement of said tool to sequentially align said first and second portions with said tool;

(e) said moveable tool comprising a central section and two outer sections, the outer sections shaped to conform with said first portion of said mandrel and the central section shaped to conform with said second portion of said mandrel.

References Cited UNITED STATES PATENTS 1,831,033 11/1931 Richter 72404 1,964,584 6/1934 Klocke 72404 652,658 6/1900 Bischoif 72404 1,552,416 9/1925 Bingham 72383 FOREIGN PATENTS 958,288 2/1957 Germany 88 CHARLES W. LANHAM, Primary Examiner M. J. KEENAN, Assistant Examiner US. Cl. X.R. 72381, 391 

